membrane separations for greener operations in the...

Membrane Separations for Greener Operations in the

Chemical Process Industries

C. Stewart Slater and Mariano J. SavelskiDepartment of Chemical Engineering

Rowan UniversityGlassboro, NJ

Session: Green Synthesis I13th Green Chemistry & Engineering Conference

College Park, MD June 23-25, 2009

Challenges and Opportunities

Process Challenge• Rising energy costs• Awareness of environmental footprint• Cost of capital investment (ROI)• Why change existing technology?Green Opportunities• Newer – energy efficient processes• Reduce waste• Waste/byproduct/material recovery

Membrane Processes

• Green alternative to process stream separations in the chemical process industries

• Product concentration, purification, waste minimization, chemical and solvent reuse and recovery

• Sustainable process - ability to recover water and valuable products from waste streams and save energy

Membrane Process

Reverse Osmosis Membrane ProcessesApplicability of membrane processes for green engineering

design in chemical manufacturing

• Applications:- Water purification for

synthesis/formulation- Water recovery in process

• Advantages:- Energy savings over

thermal processing (evaporation & distillation)

- Water reuse; water savings- Salt / reagent recovery

Water = blueSalt = red

Nanofiltration Membrane ProcessesApplicability of membrane processes for green engineering

design in pharmaceutical manufacturing

• Applications:– Solvent/API separations

• Advantages:– Energy savings over distillation– Solvent savings – no additional

recrystallization step– Solvent reuse; solvent savings– API recovery; increased yield– Avoid solvent disposal / solvent

thermal oxidation

Solvent = yellowyellowAPI = greenSalt = red

Microfiltration Membrane ProcessesApplicability of membrane processes for green engineering

design in beverage processing

• Applications:– Concentration / dewatering– “Cold” sterilization– Clarification / removal of

particulates• Advantages:

– Energy savings over evaporation

– Flavor retention– Energy savings over

Pasteurization– Capital cost savings

Beverage = blue Particles = red

www.tetrapak.com

Pervaporation Membrane ProcessesApplicability of membrane processes for green engineering design in fine chemical and pharmaceutical manufacturing

• Applications:- Selective solvent-water

separations / Dehydration- Azeotrope separations

• Advantages:- Energy savings over distillation- No entrainer (e.g., benzene)

needed for azeotropicseparations

- Solvent reuse; solvent savings- Avoid solvent disposal / solvent

thermal oxidation

Water = blueSolvent = green

www.sulzerchemtech.com

PV Process Integration

Solvent-water waste stream

Pervaporation

Dehydrated solvent for reuse

Solvent-water azeotropic mixture

Low flow rate stream: water with

some solvent

Typical Solvents• Isopropanol (az)• Ethanol (az)• Methanol• Ethyl acetate • Butyl acetate• Acetone• Acetronitrile (az)• Tetrahydrofuran (az)• n-Butanol• Methylethylketone (az)

Pharma IndustryCase Study 1 – Bristol-Myers Squibb

• Integration of PV technology with a Constant Volume Distillation (CVD) operation

• One step in synthesis of new oncology drug• Current process: Decrease water content in THF

solvent phase to 0.5%– Requires 13.9 kg THF/kg API

7.85 kg THF entrainer/kg API– Generates 9.2 kg Waste/kg API

• LCI / LCA analysis indicates emissions are significant based on solvent life cycle

Proposed CVD – PV Hybrid Process

Basis: 68 kg API / batch

6.1 kg THF/kg API0.65 kg Waste/kg API0 kg THF Entrainer/kg API

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

Life Cycle Inventory Comparison

Waste Disposal23%

THF Manufacture77%

Steam<0.1%

Waste Disposal40%

Steam54%

Electricity6.0%

Total CVD Emissions: 89 kg waste/kg API

Total CVD‐PV Emissions: 3.8 kg waste/kg API

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

• Integration of PV unit to current CVD process produces a greener process– Elimination of THF entrainer– Process waste reduced by 8.55 kg waste / kg API– Total life cycle emissions reduced by 85.2 kg waste / kg API

(96% reduction)

• Process capital acquisition not cost efficient at pilot scale– Need to produce 12,000 kg API /yr to be economically feasible

for capital investment

Pharma IndustryCase Study 1 – Bristol-Myers Squibb

Savelski, Slater, Carole, 8th Inter. Conf. EcoBalance, Tokyo, Japan, December 2008.

Pharma IndustryCase Study 2 - Pfizer

• Investigation of solvent recovery alternatives to reduce solvent waste in celecoxib process

• IPA solvent recovery from final purification steps

• Integration of pervaporation with distillation using existing equipment inventory

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

Centrifuge

IPA / Water Washes50% IPA

50% Water IPA / Water Washes

49.2% IPA49.6%  H2O0.71% MeOH and EtOH0.5% TDS

Mother Liquor

34.5% IPA45.2%  H2O8.45% MeOH2.71% EtOH9.10% TDS

Dryer

Wet Product Solids

Dryer Distillates

50.7% IPA48.8% H2O0.47% MeOH and EtOH0% TDS

Celecoxib

Conc. &  Sell ML

Recovery

SolventsWaterAPI

Other

Proposed Distill-PV-Distill Process

• Purification for only part of waste stream– Centrifuge wash and Dyer distillates for recovery– Mother liquor for (sale) use as generic solvent

• Overall 57% IPA recovered @ 99.1 wt% for reuse in process• Utilities:10,000 kg/batch of steam, 59 kWh/batch of electricity, and 91,200

gal/batch of cooling water

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

A design basis of 1000 kg waste/hr is used for illustrative purposes

Life Cycle Inventory Comparison

IPA Manufacture40%

Incineration60%

ML Distillation

19%

IPA Manufacture

59%

Dist‐PV‐Dist22%

Total Base Case Emissions: 29.5 kg waste/kg API

Total Dist‐PV‐Dist Emissions:2.4 kg waste/kg API

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

~92% decrease in total emissions

Annual Operating Costs

-1,000,000

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

Base Case Distil-PV-Distil-Sell ML

Design Case

Annu

al C

ost

ML Concentrate saleMembrane ModulesOperating LaborMaintenanceCooling WaterElectricitySteamWaste DisposalFresh IPA

72% Annual Cost Savings

Recovers 57% of IPA from waste for potential reuse

$5.28 MM

$1.46 MM

Slater, Savelski, Hounsell, Pilipauskas, Urbanski, Proc 2008 Mtg Amer Instit Chem Eng, Philadelphia, PA, November 2008,

Vibratory Field Membrane ProcessesApplicability of membrane processes for green engineering

design in food processing

• Applications:– Fluid-particle separations

• Advantages:– Efficient fluid clarification– Low fouling, enables continuous

operation– Waste disposal reduction– Operating cost reduction

Water = blueParticulates = red

www.vsep.com

Food IndustryCase Study 3 - Pillsbury / General Mills

• Water change required in bagel "cooker"–Protein waste and particulates

• Objective:–Reduce wastewater–Save water–Extend “cooker” life

ProductionLine

Feed

Concentrate for “Animal Feed”

Purified water recycled to cooker

V-Sep Membrane

Comparison of V-Sep to conventional technologies

• Capital costs less than for evaporators and rotary drum filter/concentrators

• Energy is less than evaporators, centrifuges, filter presses

• Accommodates wider range of feed flow and particulate size distributions

• Flux and selectivity maintained –elimination of cleaning chemicals

www.komline.com

Food IndustryCase Study 3 - Pillsbury / General Mills

• Cooker life doubled• Energy used to heat water saved = 1.28x108 Btu/yr• Water utilization saved = 110,000 gal/yr• Wastewater disposal saved = 110,000 gal/yr• Operating cost saved (Cooker cleaning, production

loss, waste disposal, etc) = $246,300/yr• Savings multiplied when applied to all production

lines• Potential to triple cooker life with combined V-Sep

and Centrifugation process

Summary

• Membrane processes are a viable alternative in process stream separation

Green advantage• Cost effective

–Operating–Capital

• Solvent / by-product recovery• Waste minimization• Easily integrated into process

Acknowledgements

• Bristol-Myers Squibb

• General Mills / Pillsbury

• Pfizer

• U.S. Environmental Protection

Agency P2 grant #NP97257006-0